4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

[mia9516]

During the de-winterization process I discovered that both left and right exhaust manifolds are cracked. The port side freeze plug was laying in the bilge. And the impeller is shot. My questions are the following:

1. What would be my best course of action in regards to the manifolds? Should I look for used ones, buy new ones, or can the old ones be patched up for one more season? And what are the things to watch out for when replacing them?

2. Can the freeze plug be reused and if so, how can I re-install it?

3. I knew my impeller was probably going bad at the end of last season. The temp would climb past 140 at idle and wake speeds but quickly drop when I went up on power and got on plane. Are there any other reasons, besides the one i stated above, as to why the temperature would fluctuate?

I apologize if this is drawn out but I thank any and all that can help me. Cheers!

 

[RogersJetboat454]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

1. What would be my best course of action in regards to the manifolds? Should I look for used ones, buy new ones, or can the old ones be patched up for one more season? And what are the things to watch out for when replacing them?

Replace them with brand new ones. You don't want to be buying someone Else's problems. Repairing cracked ones are a no-no.

2. Can the freeze plug be reused and if so, how can I re-install it?

First off, they are called Core plugs not freeze plugs. Old timers for some reason though they were meant to pop out and relieve the pressure of ice freezing inside the block. Sometimes they do pop out during a freeze, sometimes they don't. There actual purpose is just to cover the hole the factory used to bust all the casting sand out of the block. I would not re-use the core plugs. Get a new set for you block. One thing you must consider though is that the block may be cracked from freezing. Both externally and internally. I seriously consider looking the block over really well, checking the oil for water, and maybe pulling the intake manifold to inspect for damage. No telling if there may be cracks in your heads too. If every thing checks out, install your new core plugs. I prefer to use a little bit of Indian head shellac around the rim of the plug, and tap them into place with a socket roughly the same size as the plug. Do this so they are flush with the block. After this, you may still want to pressure test the cooling system to see if you have any leaks.

3. I knew my impeller was probably going bad at the end of last season. The temp would climb past 140 at idle and wake speeds but quickly drop when I went up on power and got on plane. Are there any other reasons, besides the one i stated above, as to why the temperature would fluctuate?

Yep, your forcing more cool water into the system. 140 doesn't sound too high. In fact it sounds cold, are you using a thermostat in the engine (you should be)? Anything over 170-175 is when you start questioning the cooling system. That being said, you should replace your impeller.

 

[Madtown_Joe]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

I just replaced my exhaust manifolds and I found the best price was on Ebay. I got a pair of GLM's. They only complaint that I have is that the notches on the manifolds in order to take out the spark plugs don't match up right. I had to take them off in order to get the plugs out. I'm not sure if this is common or not.

 

[Bondo]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

After this, you may still want to pressure test the cooling system to see if you have any leaks.

Ayuh,... I completely Agree....

Yer probably needing a new Motor, rather than just manifolds...

 

[Don S]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

During the de-winterization process I discovered that both left and right exhaust manifolds are cracked. The port side freeze plug was laying in the bilge.

Just out of curiosity, how can you de-winterize something that wasn't winterized to begin with :facepalm: :facepalm:

 

[mia9516]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

Just out of curiosity, how can you de-winterize something that wasn't winterized to begin with :facepalm: :facepalm:

My boat was winterized, for California. I moved out to Oklahoma in December and there was no way of telling that we'd have -10 degree weather with several feet of snow. This being my sophomore season, I had no idea this was even a possibility. Lesson learned. Thank you everyone for your help. Time to get some parts on order and press on.

 

[Bondo]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

Time to get some parts on order and press on.

Ayuh,.... While the odds are against ya,...
Don't call the block Scrap, til ya test it out....

 

[mia9516]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

Ayuh,.... While the odds are against ya,...
Don't call the block Scrap, til ya test it out....

I was just thinking about what my next step should be actually. I am contemplating replacing the impeller and starting the motor to see where the leaks are going to be. I've already ran motor on the 28th for two minutes @ idle. This is how I determined the impeller was completely gone due to the absence of water coming out of the exhaust. Is this a viable troubleshooting step? The motor ran fine and sounded just like it did back in Nov 2010, which was the last time it was ran on muffs in my driveway. There were no unusual noises that could be heard. I checked the dipstick and the oil looked good. I had changed it back in November as well. My reasoning is that if the block is scrap, I wouldn't need the manifolds as I'd be looking for a new motor instead. What do you think?

 

[Bondo]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

I was just thinking about what my next step should be actually. I am contemplating replacing the impeller and starting the motor to see where the leaks are going to be. I've already ran motor on the 28th for two minutes @ idle. This is how I determined the impeller was completely gone due to the absence of water coming out of the exhaust. Is this a viable troubleshooting step? The motor ran fine and sounded just like it did back in Nov 2010, which was the last time it was ran on muffs in my driveway. There were no unusual noises that could be heard. I checked the dipstick and the oil looked good. I had changed it back in November as well. My reasoning is that if the block is scrap, I wouldn't need the manifolds as I'd be looking for a new motor instead. What do you think?

Ayuh,... The oil can't get water yet,...
The water is pouring into the bilge....

I'd skip the impeller at the moment,... 'ell, pull the drive...
Then after you put the coreplugs back in, stuff a garden hose into the in-bound waterline, at the T-stat, 'n light it off...
by-pass the manifolds for the test..
If water ain't sprayin' out into the bilge, or worst yet, filling the oil pan,..
Ya mighta gotten really, Really Lucky...

 

[mia9516]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

Ayuh,... The oil can't get water yet,...
The water is pouring into the bilge....

I'd skip the impeller at the moment,... 'ell, pull the drive...
Then after you put the coreplugs back in, stuff a garden hose into the in-bound waterline, at the T-stat, 'n light it off...
by-pass the manifolds for the test..
If water ain't sprayin' out into the bilge, or worst yet, filling the oil pan,..
Ya mighta gotten really, Really Lucky...

Sounds good Bond-o! I'll give that a shot and report my findings ASAP! Thanks again!

 

[mia9516]

Re: 4.3LX Cracked Exhaust Manifolds, Freeze Plug, and Impeller Question

The boating gods have taken pity and smiled upon me this day fellow boaters!!!:-D I performed the test that Bond-o recommended and there was absolutely no oil in the oil pan. I am very relieved that the block was not damaged due to my ignorance:-/. I will now be ordering a set of new mani's from www.perfprotech.com for a mere $140 plus $10 shipping here in the Sooner state. My boating season should be starting shortly. I am sure I will be in contact once my parts come in and I am once again dumbfounded...HAHAHA!!! Cheers!